If you encounter build-dependency errors, you should try first to lower the dependency in debian/control, both in Build-Depends and in Depends and re-run debuild.
If the build fails (e.g. with undefined reference to `ev_run') the previous version is missing required functions. So, you must install the updated versions of the required dependencies (e.g. libev4) from sid, using apt-get install name=version e.g. libev4=1:4.11-1. I suggest this because you’ll have to manually update packages installed from sid, so the lesser, the best.

So you have a Linux VM you use for development, because you want to mirror the production environment as closely as possible. You have many applications to deal with, they have to be running at the same time because they are nifty REST JSON web services.

You are very tired to remember which one you put on port 8081, and your configuration files slowly become a real mess. So you set up IP address aliases in for the network interface and decide to assign even host names – /etc/hosts is just fine – for each app.

Then, in such a setup, why would you still need to run them on ports higher than 1024? Wouldn’t be just great to type the application name in the browser address bar? Indeed it is, but it’s better to not run them as root, anyway.

The solution are Linux capabilities (see also here). The one that interests us is cap_net_bind_service: it gives a process the right to bind well-known ports (< 1024). If you use an interpreted language, of course you’ll have to add the capability to the interpreter itself. That’s why there’s development in the title of this article – you should not set this up on a production server, if you don’t know what you are doing.

One final quirk: if you happen to dlopen() shared objects that dynamically link towards libraries outside the canonical paths, you cannot load them via LD_LIBRARY_PATH (e.g. the SYBASE.sh) as it is ignored for setcap-ped processes. You should better move the library paths into an /etc/ld.so.conf.d snippet.

tl;dr

Assuming you are the latest and greatest rails developer, you should become root – or use sudo, as you wish – and

# YOU ARE ON YOUR DEVELOPMENT MACHINE
setcap cap_net_bind_service+ep `which ruby`

“If it is good, they stop making it”, the payoff printed on the conference necklaces, distributed to every participant, along with an über-l33t badge customized with our nickname and the key hash.

Being my first experience at an international security conf (I’ve only been to the ccc2k+7 camp), and being a ph outsider ‘cause I never participated to previous editions, the boot keynote held by FX, staffer and frontman, has been enlightening: “you ought to be here!”, he yelled while pointing at the stage, wearing a white shirt with the Phenoelit logo printed on both arms.

“This conference has never started on time”, he continued, “so there was no reason to do that for this last one”. the schedule is straightforward: party, the next days talks from 12.00PM to 7.30PM, then party, and the last days talks from 12.00PM to 5.30PM. definitely a setup well-playing with the available alcohol :-D.

Afterwards, another speaker informed us that the wi-fi access keys we received at the registration allows us to use a 6 APs/3 repeaters beast driven by an OpenBSD box – they want the audience to hack it because, well, “you are the Worst Case Scenario.” :-)

Thanks to @jodosha efforts and praising the former Javaday event, now renamed into codemotion that brought in Rome many Ruby developers from Milan, Padua and other parts of Italy – the first official Ruby Social Club in Rome has been a great success. Of course, officialty is measured only in the amount of twitter spam posted about it! :-): earlier RSCs in Rome go back in time to 2006 organized by current mikamai members and more meetups promoted by @jekoin 2007.

What matters is that there's a community, there's a passion, and there's love to share knowledge - no matter who holds the meetings, the important thing is that they're being held :-).

The event was simple and direct - some beers first, then my keynote on RVM and Ruby interpreters, then Luca's one announcing his minege.ms project and after real social networking :-). I met @gravityblast after much time we didn't meet, knew the PIP group and met @svarione, @punkmanit, @leonardoperna, @riggasconi@ogeidix and other smart people. Moreover, we spent quite some nice time together, making up a really lousy and funny week-end.Of course, huge kudos to @nhaima's car - that tirelessly carried us around Rome for two days :-)

Now, looking forward to the next meetup, thanks everyone who participed, who offered me beers and, last but not least, thanks to @etapeta for bringing me in time at the meeting - you're the real hero :-).

I spent the last two days trying to set up the Aluminium Mac Mini (rev. 4,1) as a home NAS server with encrypted storage, and I wanted a BSD system on it. There’s already an embedded OpenBSD onto the soekris gateway, and another companion would have been nice. :-)

FreeBSD 8.2-RC1 boots but, due to the same bug, doesn’t recognize any SATA drive nor any USB umass device;

NetBSD 5.1 boots fine, handles SATA disks via the generic pciide driver (no DMA, thus quite slow) but, unluckily, doesn’t handle the BCM57762 ethernet controller. I tried with quick and dirty patches to bring the bge driver up to date with -current, but still no luck: the MII link detection works, the card transmits but doesn’t receive. The sdmmc controller as well works with -current but not with 5.1-RELEASE. ACPI works correctly;

OpenBSD 4.8 boots, can access the SATA drives without DMA, and recognizes the bge network card, but exposes the very same behaviour as NetBSD 5.1 with the -current driver fitted in;

DragonFlyBSD 2.8.2 doesn’t even enter kernel mode, I suspect due to ACPI bugs;

All of them support encrypted storage, I built up a NetBSD CGD disk flawlessly onto dk wedges; FreeBSD has got the interesting gbde(8) and geli(8) GEOM-based tools that I wasn’t able to test, while OpenBSD supports crypto via a softraid personality. Unluckily, support for the, nowadays, exotic Apple hardware is a no-brainer.

So, with no other way left open, I decided to go the Linux route, using the excellent sysresccd, that I elect today as the successor of the pld-linux rescuecd, companion of endless system recoveries :-). Anyway, you’ll need the 2.6.36 kernel to make it boot onto the MacMini4,1, due to the aforementioned MCP89 bug. Ethernet card and SD card reader work out-of-the-box.

Now, I’m playing with LUKS and, while I’m not that competent in cryptography, looks like it is more evolved than the *BSD counterparts, and anyway it is more versatile tool than the tools in OpenBSD and NetBSD. On the latter, having to set up GPT and DK Wedges to make the CGD and synch MBR and Disklabel to make the boot loader work (yuck!), everything coupled with rEFIt is quite a mess™. There’s a GPT loader for NetBSD but I hadn’t a chance to try it out.

I hope this information is useful to anyone who tries a similar adventure, comments are appreciated :-).

Out of curiosity, I was looking how a browser interacts with the Google Instant backend. While looking the HTTP exchanges via Firebug, I first asked myself why they’re encoding HTML and JS with \xYY escape sequences, then why the very same JS functions are sent back and forth on every request, and later I stumbled upon the google.com/s?q=QUERY JSONp service.

Give it a query, and it’ll return the suggested related phrases that are used to build the menu under the search input while using suggestions and/or instant (didn’t dig too much in all the other parameters).

Anyway, what’s interesting is that, of course, the suggestions are customized on a per-country basis. To show the differences explicitly let’s ask the service the simplest query possible, a:

I’m sure @nhaima is smiling while seeing these words, because hell yeah, over there they really google antivirus software (avira is one of them) a lot because it’s a world without the Internet, thus without free software: you’re condemned in using Windows stuff, and you take what you pay for. Antonio Maceo has been an hero of the 19th century revolution, and it’s in the heart of Cuban people. Amor, Amigos! :-)

Anyway, looks like that simple queries like this really give an insight on what a population thinks and/or needs, because they’re surely generated by the search trends, thus are the “most searched words”. Am I discovering hot water? Maybe, but it was funny to rediscover it. Just make sure not to hammer the /s service with too many requests, because they’ll anyway be handled by the same cluster of machines, thus you’ll be banned early (I’ve been :-p).

On July 22nd 2010, Mikamai hosted a Ruby Social Club in Milan, where nearly 50 people attended watching five speeches about Ruby, Web development and Startups. I was glad to be one of the speakers, and I presented a set of Rails plugins we spinned off from our latest (and greatest) project: Panmind (read more on the about page) and released as Open Source on GitHub.

The keynote is split in two parts: the first one explains why you should follow the sane software engineering principle of writing modular and interest-separated code and then how you could (and should) extract it from your Rails application by decoupling configuration and then prepare for the Open Source release, by writing documentation AND presenting to a Ruby event so, hopefully, someone else will write unit tests! :-)

We released an SSL helper plugin that implements filters (like Rails' ssl_requirement) but also named route helpers: no more <%= url_for :protocol => 'https' %>! You'll have something like plain_root_url and ssl_login_url - like they were built into the framework.
Then, a Google Analytics ultra-simple plugin, with <noscript> support, a couple of test helpers and an embryo of a JS Analytics framework - hopefully it'll evolve into a complete jQuery plugin. Then, a ReCaptcha interface, with AJAX validation support and eventually a Zendesk interface for Rails.

As most of you already know, there are two open, critical vulnerabilities in iPhone OS versions from 3.x up. The first one resides in the Compact Font Format component of the PDF renderer and the second one an error in the kernel, allowing attackers to bypass the sandbox (SeatBelt) inside which applications are run on the iPhone.

The two vulnerabilities were discovered by @comex, @chpwn and other people.

Only few weeks later the .lnk design flaw on windows (guys, you’re using LoadLibraryW to load a damn icon!), these iPhone OS vulnerabilities are even more interesting, because of the way the release is being handled by the community and the vendor.

I spent 3 hours last night trying to find detalied information about the bug, and except confused (and propagandistic) blog posts the only bit of information is in this tweet, and in the actual pdf exploit running on jailbreakme.com. Where are the security lists posts? Where is the CVE? Even the CERT still doesn’t say anything about this vulnerability.

There’s something terribly wrong going on: the cat-and-mouse-game that is making the iphone-dev team researchers not disclose any of the vulnerabilities they find has become very dangerous for end users: an exploit that allows remote code execution and jail escape without no interaction whatsoever by the user, carried via something that’s used to consider “safe” (a PDF file) is what is called a critical hole; while the exploit that uses it is called a 0-day. It’s the first time in my life I see a 0-day packaged and distributed explicitly via a web site.

Anyway, the dev-team researchers did not have any other choice: if they had communicated with Apple prior to public disclosure, we wouldn’t have had a so easy jailbreak vector; OTOH now we have vulnerable phones and pads that can be very easily exploited by mailcious parties. It’s also funny that in order to be warned when a PDF is about to be loaded thus mitigating the risk, you should jailbreak your device and install the PDF Loading Warner afterhand.

My stand on this is that the real problem is Apple itself: they’ve crated a walled garden, outside any legislation, where they’re the absolute god and give and take whatever they want. It’s not gonna work forever. I really hope that people will understand think that it’s not the hackers’ fault, rather it’s the totalitarian companies’ fault, for not giving us control over the devices we buy from them. Hackers are only trying to liberate them, and it’s fair use under the DMCA, after all.

UPDATE 2010-10-05: I’ve posted a summary of this bug on the full-disclosure mailing list – you know, if it’s not on FD no one would think about it :-).

In a nutshell, it adds support for unmarshaling 1.9 strings, and implements the last missing type (TYPE_LINK) that was missing from the code. Tests still lack, can someone help ? :-)

Added TYPE_LINK, needed because of how ruby 1.9 marshals strings.
In 1.9, Ruby marshals the string encoding in the binary output, and
uses an Ivar construct (TYPE_IVAR) to wrap the string and adds an
"encoding" instance variable (notice: without a leading @) whose
value is the encoding itself.
While the Ivar code worked correctly, the values of the encodings
are actually *strings*, that are being reused via the TYPE_LINK
construct, that wasn't implemented.
So, the get() and put() primitives are being used to store not
only tuples {id, sym} for symbols, but now store either
{{symbol, ID}, sym}
OR
{{value, ID}, val}
for the other types that use TYPE_LINK.
By reading the ruby marshal.c source code, it looks like that MANY
data types save their values in the arg->data hashtable, but by
inspecting the binary marshal output of, e.g, an array of floats,
links aren't used.
Thus, in this unmarshaler, links are considered, for now, only for
strings and regexes.

This is sindro.me, a weblog by Marcello Barnaba (@vjt) about technology, ruby, development, software, the internet, entertainment, politics, sociology, and the answer to Life, Universe, and Everything (42).